The invention relates to a valve, in particular for the fluid circulation in a motor vehicle[, as generically defined by the preamble to the main claim]. Such valves are used to block fluid flows or throttle them or distribute them. To that end, such a valve has at least one inlet, one outlet, and a valve member that monitors the passage between the inlet and the outlet. The valve member is embodied as flap, which can move in the passage and varies or closes the flow cross section. Great effort must be expended to put the flap securely into the application determined position.
In accordance with the invention, a valve is proposed which has a valve for a fluid circulation in a motor vehicle, comprising a housing having at least one inlet and at least one outlet that communicate with one another via a passage; a valve member formed as a movable flap that monitors said passage, said passage having a chamber in which said flap is disposed and into which said at least one inlet and said at least one outlet discharge, said flap being pivotably supported in said housing; a drive mechanism which shifts said flap from a first terminal position to a second terminal position, wherein said terminal positions form an angle a that is smaller than 90xc2x0.
The valve of the invention has the advantage that the flap has to be swiveled over n o more than a small range, so that the expense for both driving it and sealing are reduced considerably. The valve can also be designed to be smaller and more compact, since the chamber receiving the flap can also be kept smaller. Since the terminal positions of the flap as a rule correspond to the position of the outlet openings, a streamlined passage is created, reducing the flow resistance.
An even further improved flow passage is obtained if the terminal positions form an angle xcex1 of less than 60xc2x0 and preferably less than 45xc2x0. It is also advantageous if, in this valve that has two outlets, the outlets form a second angle xcex2 to one another that is again less than 90xc2x0 and preferably equal to the angle xcex1 formed by the terminal positions of the flap. In this way, a very compact, slender valve is created, which is distinguished by low flow resistance, because the deflections are few and slight.
If the cross section of the mouth of the inlet into the chamber receiving the flap is smaller than the chamber, thus producing an edge surrounding the mouth region, edge eddies develop that have the effect that the flows press against the chamber wall and thus further reduce the flow resistance. It is helpful if the cross section of the inlet tapers in the direction of the chamber and in particular assumes a rectangular shape. With this kind of embodiment, an optimal flow passage is achieved. It is equally advantageous if the outlet discharge opening toward the chamber is also rectangular, especially since whenever the flap cooperates with this mouth, the largest possible flow cross section can be established. Preferably, the housing is in two parts and has a base part and a cap part, and the base part receives the flap bearing, and the at least one outlet is formed onto the base part and the at least one inlet is formed onto the cap part. This design is economical and easy to assemble, because only a few individual parts are needed. The cap part can be simply placed on the base part and locked there. Special fastening means are not needed.
If the flap is supported in the chamber in a region opposite the inlet mouth, and if in particular the flap extends from the bearing to the inlet mouth and tapers to a point on its end opposite the bearing, the force required to move the flap can be kept small, because on the one hand hardly any dynamic flow pressure has to be overcome to move the flap out of a terminal position, and on the other because the flap extends directly in the flow direction and therefore hardly presents any resistance to the flow, and beginning at a middle position, the flow itself reinforces the flap motion.
With an elastomer sheath surrounding the flap, on the one hand a simple sealing of the outlet discharge opening can be attained, and on the other, the region of the bearing of the flap can simultaneously be sealed off from the housing. It is advantageous if the chamber has conical faces, which cause a tapering of the chamber in the direction of the bearing. Upon insertion of the flap, the elastomer sheath rests on the conical faces, and as the flap is inserted, the elastomer sheath is compressed in the direction of the bearing region to the pressure required for the sealing.
The flap is preferably urged by an elastic means into a preferential position, such as the middle position, so that if the drive mechanism fails, a defined state can be established automatically. The elastic means is likewise advantageously formed by the elastomer sheath, which engages a recess in a chamber wall.
The flap bearing which has a shaft passing through the housing wall, is preferably also embraced outside the housing by a sealing element, which in turn is secured to the housing. The sealing element provided for this purpose has a shaft seal on the one hand, and on the other a seal similar to an O-ring seal in the outer region, as well as a sealing cap surrounding the end of the shaft. Both the shaft seal and the sal similar to the O-ring seal are structurally connected to the housing and prevent the fluid from creeping out. The drive mechanism engages the sealing cap, which also acts as a sealing means and surrounds the shaft end, from the outside and acts on the shaft end, which is for instance square. This region of the seal thus moves together with the shaft end and can accordingly be completely closed. This creates an absolutely reliable seal. This type of seal becomes possible because the angle a between the terminal positions of the flap motion is designed to be less than 90xc2x0, and preferably less than 60xc2x0 or 45xc2x0.